Concha bullosa, a pneumatized middle turbinate, is a common anatomic variant found in the paranasal sinuses. When a concha bullosa becomes obstructed, it can form a mucocele and, eventually, a mucopyocele if it becomes secondarily infected. This is a rare phenomenon; only 9 concha bullosa mucopyoceles have been previously reported in the English-language literature. We present the case of a large concha bullosa mucopyocele in a pediatric patient in which the concha bullosa replaced the anterior ethmoid sinuses and was contiguous with the frontal sinus.